Fuel injection system



Jan. 28, 1964 v, RQOSA 3,119,437

FUEL INJECTION SYSTEM Filed Oct. 51, 1960 2 Sheets-Sheet 1 FIG. I

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FUEL INJECTION SYSTEM 2 Sheets-Sheet 2 I I I I I FIG. 4

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VERNON D ROOSA ATTOR NE Y5 United States Patent 3,119,437 FUEL INJECTHQN SYSTEM Vernon D. Reosa, Hartfcrd Machine Screw Co., 1 .0. Box 1440, West Hartferd 2, Cc-nn. Filed Oct. 31, 196i), Ser. No. 66,294 1 Claim. (Cl. 158-463) This invention generally relates to fuel systems for internal combustion engines and is more particularly concerned with an improved fuel injection system that includes protection against malfunction of the injection system due to clogged fuel feed lines.

It is customary to place one or more filters in the fuel feed lines to the pump of a fuel injection system, and these filters must be changed before clogging reduces their efficiency so as to impair fuel pump and engine operation. Visual inspection is rarely sufficient to reveal filter clogging and the alternative of periodic filter replacement rarely produces efiicient filter use.

It is therefore a primary object of this invention to provide an improved fuel injection system which accurately detects filter clogging or the like in the fuel feed to the pump.

It is a further object of this invention to provide an improved fuel injection system wherein the fuel line clogging detector is fail safe as regards the operation of this system while being economical to manufacture and reliable in operation.

It is an additional object of this invention to provide an improved fuel pump that incorporates a detector for sensing malfunction of the fuel feed thereto, particularly the necessity for changing fuel filters.

It is a still further object of this invention to provide such an improved fuel pump wherein the detector is fail safe and does not affect the normal operation of the fuel pump and which is small in size and economical to manufacture and install.

Other objects will be in part obvious and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereafter set forth and the scope of the application which will be indicated in the appended claim.

In the drawings:

FIG. 1 is a schematic view showing a portion of my improved fuel injection system;

FIG. 2 is a vertical cross section view of a portion of my improved fuel pump; and

FIGS. 3, 4 and 5 are schematic circuit diagrams illustrating indicator circuits for use in my improved fuel injection system.

Turning first to FIG. 1 of the drawings, it is noted that my improved fuel injection system includes a main fuel tank It} from which fuel is supplied to filter 12 through line 14 so that filtered fuel is supplied to fuel pump 16 through line 18. In the preferred embodiment pump 16 is of the type shown in my prior Patent No. 2,641,238 entitled Fuel Pump which includes within the housing 20 a fuel transfer or pickup pump generally designated 21 and a fuel distributing pump generally designated 22. Power is supplied to pump 20 through shaft 24 so as to rotate transfer or pickup pump 21 to draw filtered fuel through line 18 into pickup pump inlet passage 26 from where it is transferred to distributing pump 22 and to the various cylinders of the engine through outlets 27. In the event that fuel filter 12 becomes clogged or lines 14 or 1% become obstructed, the inlet of pickup pump 21 is starved so as to cause engine malfunction.

According to the present invention, proper filter life is obtained and warning of fuel feed system clogging Patented Jan. 23, 1954 is given through the provision of a pressure-sensitive switch mounted integrally with pump housing end cap 39. As most clearly seen in FIG. 2, end cap 30 contains fuel inlet passage 26 and is provided with a recess 32 adjacent the lower end of inlet passageway 26. Recess 32 is closed by cover or cap 34 which is secured to end cap 30 in any suitable manner such as by staking at 35. Prior to securing cover 34 to end cap 30, diaphragm assembly 36 is positioned over recess 32 and is trapped between shoulder 38 of cap 30 and end face 40 of cover 34 in sealing engagement therewith so as to define a first compartment designated 41 and a second compartment designated 42 separated and sealed from each other by diaphragm assembly 36.

Diaphragm assembly 36 includes a flexible neoprene or the like membrane or diaphragm 44 having a first or rear plate 46 and a second or front plate 48 secured thereto by rivet 49 which forms the first contact of a pressure-sensitive switch assembly. An electrically conductive spring 50 is disposed between the inner wall of recess 32 and plate 46 to urge the diaphragm assembly to the position shown in FIG. 2 wherein second plate 48 is in engagement with shoulder 52 of cap 34.

Contact screw Gil, the second contact of the switch assembly, is supported in internally threaded bore 62 of terminal 64 which, in turn, is supported in an aperture as in cover 34 through the engagement of terminal flange 63 and terminal locknut 70 with terminal insulating washer 72. Washer 72 not only insulates contact screw 60 and terminal 64 from cover 34 but also acts to seal aperture 66 against leakage. Terminal screw 76 is also supported in threaded bore 62 of terminal 64 and serves to establish electrical connection to contact screw 60.

Movement of diaphragm assembly 36 in response to pressure conditions in inlet passage 26 is achieved by providing drilled passageway 78 extending from first compartment 32 to inlet passageway 26. Spring St is selected to exert a predetermined outward force on diaphragm assembly 36 so that under normal fuel system operating conditions contacts 49 and 66) remain in engagement as fuel is drawn through inlet passage 26 by the pickup pump. As the filter 12 or any other portion of the fuel feed system becomes choked or clogged, pickup pump 21 creates a vacuum on the inlet side thereof, i.e., pressure in inlet passageway 26 is reduced. When the pressure falls below a predetermined quantity as determined by the preselected characteristics of spring 5%, pressure acting on side 43 of diaphragm assembly 41 causes the assembly to move against the force of spring 5!) thereby opening the contacts. As is clearly apparent from FIGS. 1 and 2, this novel pressure-sensitive switching assembly is integrally mounted with the fuel pump with minimum increase in the size and weight thereof. lf desired, this switching arrangement can be provided as an accessory for a fuel pump simply by interchanging a new end cap for the old cap.

Turning now to suitable indicating systems for visibly, audibly or otherwise signaling the condition of fuel feed portions of the injection system, (FIGS. 3-5) it is noted that DC. current from battery 80 is supplied to fuel pump shutoff solenoid 82 through manually operated switch 84. Solenoid 82 is of the general type shown in my prior Patent No. 2,538,982 and is preferably contained within the control mechanism chamber generally designated 85 in FIG. 1. In the preferred embodiment this solenoid is used as shown in the referred patent to close the pump inlet metering valve so as to shut off the supply of fuel to the engine when solenoid 82 is de-energized by opening of ignition switch 84.

In the circuit of FIG. 3, contact 49 in end cap 30 is connected to the system ground through conductive spring t) and contact 60 is connected to fixed contact 88 of switch 84 through indicator solenoid 86 and wire 87. Indicator 96 has one side connected to the ground and the other side connected to contact 88 through solenoid contact assembly 91. Under normal operating conditions closing of ignition switch 84 energizes solenoid 82 to permit operation of the engine and energizes indicating solenoid 86 through normally closed contacts 49 and 60 to hold solenoid contact assembly 91 open and indicator 9t) de-energized. Indicator 99 can be any suitable device such as a bell signal, lights, etc. Upon occurrence of a clogged filter or similar malfunction of the fuel feed system, contact 49 is moved away from contact 69 as previously explained thereby de-energizing indicating solenoid 86 and energizing indicator 90 to signal the fuel system malfunction.

The circuit of FIG. 4 is similar to that shown in FIG. 3 except that indicator 90 is connected so as to be energized whenever the system is normally operating and thereby de-energized upon occurrence of a malfunction which opens contacts 60 and 49.

The circuit of FIG. 5 connects engine solenoid 82 through contacts 60 and 49 so that, upon occurrence of a clogged filter condition or the like in the fuel feed system, solenoid 82 is de-energized thereby closing the fuel metering valve. Before the engine stops completely the reduction in speed of the pickup pump permits inlet pressure to rise from the vacuum condition thereby permitting contacts 60 and 49 to again close and energize the engine operating solenoid 82. The circuit of FIG. 5 thus causes intermittent energization of solenoid 82 to signal the clogged filter or fuel feed condition by intermittent engine operation.

FIGURE 6 schematically illustrates the circuit of FIG- URE 5 with the generalized system of FIGURE 1 wherein the fuel from tank 10 passes through filter 12 via fluid lines 14 and 18 into fuel pump 16 within the housing of which is located a pressure sensitive switch, a pick-up or transfer pump 21, a throttle valve 92 having an operating solenoid 82, an injection pump 22, and a distributor such as is disclosed in my aforementioned United States Patent 2,538,982. The control circuit includes a battery 80 and a main or ignition switch 84 connected through solenoid 82 of valve 92 to control operation of the valve 4. 92 and therefore the injection pump 22 in accordance with the pressure in line 18.

From the foregoing description of the preferred embodiment of my improved fuel injection system and fuel pump together with the explanation of the operation of this embodiment in combination with various indicator circuits, it is clear that this invention provides an inexpensive, accurate and reliable clogged fuel feed-sensing arrangement which is fail safe while accurately indicating the condition of the fuel feed system.

As will be apparent to persons skilled in the art, various modifications and adaptations of the structure above described will become readily apparent without departure from the spirit and scope of the invention, the scope of which is defined in the appended claim.

I claim:

A fuel injection system for an internal combustion engine comprising a fuel pump having a housing, a solenoid operated valve mounted therein for shutting off the supply of fuel to the pump upon-de-energization thereof and an inlet passage through which fuel is drawn by the pump for distribution to the engine, a fuel filter, means for supplying fuel to said fuel inlet passage through said fuel filter, a pressure-sensitive switch supported by said housing adjacent to said inlet passageway, said pressure-sensitive switch having normally closed contacts, means communicating between said pressure-sensitive switch and .said inlet passageway whereby a drop in inlet passageway pressure occasioned by clogging of said fuel filter causes actuation of said switch to open said contacts, and electrical circuit means connecting said switch in series with said solenoid operated valve whereby clogging of said filter causes deenergization of said solenoid operated valve.

References Cited in the file of this patent UNITED STATES PATENTS 1,908,088 Warner May 9, 1933 1,974,779 Lupold et al. Sept. 25, 1934 2,066,267 Hayes Dec. 29, 1936 2,269,705 Besler Jan. 13, 1942 2,499,494 Greer Mar. 7, 1950 2,799,852 Barnes July 16, 1957 2,943,446 Goodall et al. July 5, 1960 

